GH2 Image sizes

Discussion in 'Panasonic Cameras' started by soundimageplus, Sep 21, 2010.

  1. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    About the only thing I can understand from the Japanese Press Release is the image sizes!!

    Panasonic Lumix GH2

    They are as predicted -
    4x3 is 4608 x 3456 16MP > 45MB
    3x2 is 4752 x 3168 15MP > 43MB
    16x9 is 4976 x 2800 14MP > 39MB
    1x1 is 3456 x 3456 12MP > 34MB
     
  2. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Based on what? My GH1 RAW images in 16:9 are 12.3MB, and 6.2MB in JPEG. Surely they open up a lot bigger in 16-bit Photoshop, but for storage they're pretty small. Why would the image size jump from 12MB to 39MB with only a 1.33x increase in resolution?
     
  3. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    I'm not quite sure what you mean. Are you taking about compressed .jpg size or mega pixels?

    I'm quoting the full size of the image and not when its stored in a compressed form.
     
  4. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    I'm talking about the amount of space the in-camera RAW files take up. They're only 12MB for my GH1. When I open them up in 16-bit mode with Photoshop they bloom to 65MB, but that doesn't fit your numbers either. I'm just wondering what those file sizes represent.
     
  5. ChristopheG

    ChristopheG Mu-43 Regular

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    Jun 4, 2010
  6. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    The file size refers to the size in MB of the file when it opens in Photoshop in 8-bit mode. Its the size of the file if saved as an uncompressed 8-bit tiff. It refers to picture library and publishing requirements and gives an indication of the resolution of the file when its being considered for publication. Only 8-bit 300 ppi files are used for the majority of the print media, magazines, books etc. This has nothing to do with domestic printing. Its a print industry standard.

    Many stock libraries or picture buyers want to know the "size" of the file as it indicates to them what size they can print it. For example a 48MB+ file indicates that its printable to A3 size. Several picture/stock libraries use this 48MB size as a minimum requirement for accepting images. Some will accept smaller sizes interpolated up to this size, some won't.

    A camera that produces a file of 17MP+ will generate an 8-bit file that is larger than 48MB without interpolation and this is a requirement for many libraries, agencies and publishing houses.

    This "full-size" figure is also used in film scanning. Negatives and slides that are going to made available for publication will usually be scanned to produce an 8-bit file that is larger than 48MB when opened up in software, Photoshop for instance.

    When you open up one of your GH1 jpgs for example in Photoshop you will see that its just over 34MB in size. This is the size that I'm referring to.

    The largest size that the GH2 will produce in 4 to 3 ratio, is 45MB. This indicates to picture libraries, publishers etc. that the file has enough resolution to be considered for A3+ printing. While it may be perfectly possible to print A3 from a smaller file, either interpolated or not, certain libraries agents and publishers won't accept files below a certain size.

    Whether you think about the size of a digital camera file in terms of MP or MB is a matter of choice, but I've made my living for many years shooting stock photography and this is what I'm used to.

    The size of a file when its stored is a different matter. Jpgs use compression to reduce the file size for storage and internet delivery. By changing the amount of .jpg compression you can change the size of your file. Though higher .jpg compression means smaller file sizes but a reduction in quality. Raw files organise data in a different way and can also be shot and stored in a variety of sizes, depending on whether you compress them or not. Nikon for example offer several alternatives for shooting raw files. Plus there are a range of options when converting files to .dng files, which alter the file size. These alternatives all produce different sized files for storage.

    So the file sizes that I put in my original post are the sizes of the images at 8-bit in Photoshop. As I indicated this is a figure that is significant for many of us who sell pictures for print publication.
     
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  7. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Thank you for the detailed explanation. That's what I was asking. I'm sure not a lot of people on this forum sell pictures for print publication, so the numbers you quoted by themselves didn't mean anything. Now it makes sense.
     
  8. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    I was explaining why the image size is important for me. As said by someone else its the size of your jpg out of the camera. I think most people are aware of that.
     
  9. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    628
    Feb 12, 2010
    San Diego, CA
    Thank you again. For me, the only image size I'm aware of and care about is the stored image size on my drive, because that tells me how many photos I can store. I think most people are aware of that, and not the expanded image size when you open it up in Photoshop since that gets compressed again when you save it, so the 33.2MB number that Photoshop displays when I open up my 6.2MB JPEG doesn't mean a whole lot to those of us who don't print professionally. That's why you quoting those numbers without any sort of reference to what they mean was confusing, prompting me to ask for clarification. Sorry if that bothered you.

    I don't want to read too much into your replies, but I get the sense that I insulted you in some way, so I'll just drop it. No such thing was intended, and I got in trouble for that before on these forums. Moving on.
     
  10. dko22

    dko22 Mu-43 Regular

    163
    Jul 26, 2010
    Stuttgart, Germany
    thanks for this interesting explanation which has, however left me rather puzzled! You are suggesting then that the output of a camera like the D3 with a mere 12mp would not be accepted by many libraries? If that's really the case then the requirements must be constantly shifting as a couple of years ago there were hardly any 17mp cameras (in 35mm at any rate)
     
  11. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    Its pretty rare for a library not to accept a D3 file, but they do exist. There were those that wouldn't accept 35mm film either. There are still a few that won't accept digital!

    You are right about the requirements constantly shifting, they do. Cameras that were perfectly acceptable a few years ago are no longer so.
     
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  12. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    Alamy

    To follow up on this, Alamy, the UK picture library who have probably the largest stock online of any library in the world, have just dropped their minimum file size requirement from 48MB to 24MB.

    Reason unknown as yet.